Modern telecommunication networks include many different types of technologies. IP networks represent one type of network where IP packets are transmitted across the network. The public switched telephone network (PSTN) represents another type of network. Networks may also combine different types of technology. For example, a voice over IP network (VOIP) carries voice calls in packet form.
In order to connect users across networks, different functions, for example, trunking, may be performed. Trunking involves transmitting information between two endpoints, for example, between switching centers. Calls and information transmitted in the trunked lines may be managed for maximum efficiency.
Information may be transmitted across networks using different types of protocols, for example, the Session Initiation Protocol (SIP), which is utilized by various network elements. A typical SIP-based system may include SIP gateways, SIP proxy, and a backend system. The SIP gateways may interface with the PSTN network through trunk lines. For example, these trunk lines may be T1, PRI, and T3 lines. Other examples of elements in a SIP system are possible.
A trunk may be a DS0 or any other example of a connector between switching systems. The purpose of the trunk may, for example, be to transmit a call between switching centers.
The SIP proxy may manage the SIP gateways within the IP network and may facilitate call authorization, routing, and billing. The proxy may perform other functions, as well.
The proxy may manage the gateways. For example, the proxy may identify the gateways by the IP address. The proxy may perform other functions, as well.